This invention relates to battery separators and is directed more particularly to a separator for use between the electrodes of Ni-Cd and Ni-Zn alkaline electromotive force (EMF) cells or batteries.
In recent years there has been an upsurge of interest in the electric automobile due to pollution problems with internal combustion engines and, also, because of the energy crisis. Accordingly, there has been a parallel increase in work on batteries or cells suitable for powering electric vehicles.
Lead-acid batteries have been used in the past for electric automobiles and are currently in use for dollies and vehicles used in factories. The high-weight and expense which results from providing a sufficient number of batteries to achieve a practical range of operation for an electric automobile is too great to make such vehicles acceptable to the general public.
Prime candidates to replace the lead-acid battery are the Ni-Cd and Ni-Zn alkaline batteries. However, it has been found that the nickel electrodes of such batteries are subject to warping after relatively short usage. This requires that the separators between the nickel and zinc or cadmium electrodes be highly flexible so as to prevent cracking and disintegration of the separator and the consequent shorting of the electrodes.
Another objective which must be met with regard to Ni-Cd and Ni-Zn alkaline batteries is the reduction of cost to an acceptable level. Because the cost of the separators is a significant portion of the total cost of an Ni-Cd or Ni-Zn alkaline cell, a reduction in the cost of manufacturing separators is an important factor. Thus, a separator which utilizes low cost materials and which is easy to manufacture is desirable.